PSG were under pressure early on but came to life after 20 minutes when an exchange between Messi, Kylian Mbappe and Neymar almost bore fruit as the Brazilian’s low shot from inside the box went just wide.
Achraf Hakimi was denied by Jean-Louis Leca and Mbappe missed two clear chances as the hosts upped the pace, but Lens also threatened through Seko Fofana and Jonathan Clauss.
PSG were booed by the crowd at halftime.
Kevin Danso picked up a second yellow card for a rough tackle on Neymar in the 57th minute.
On the resulting free kick, Leca had to fully stretch to parry away Messi’s attempt.
The Argentine forward curled a perfect 25-yard shot into the top corner in the 68th minute after being set up by Neymar.
Part of the crowd chanted Messi’s name but ultras from the Auteuil stands left the stadium seven minutes later.
The move put a dampener on the upcoming celebrations of the club’s only title this season, which left Marco Verratti as the only player on Ligue 1 history with eight league titles.
Lens, who had won their three previous games and are still hoping to finish in the top three, are left in seventh place on 54 points, five behind Monaco who beat St Etienne 4-1 away earlier on Saturday.
The game at Geoffroy Guichard was interrupted for almost half an hour after fireworks were lit in the stands.
Lyon hit five past Montpellier to boost Euro chase
Lyon pulled to within four points of a Europa Conference League play-off spot by beating Montpellier 5-2.
Moussa Dembele notched his 16th league goal to give Lyon the lead with a strike into the far corner in the 26th minute.
Brazilian midfielder Thiago Mendes doubled the lead with a curling free kick in the 43rd minute that hit the bar before bouncing in off goalkeeper Jonas Omlin.
Lyon blew the lead in first half injury time. Montpellier captain Teji Savanier fed Elye Wahi, who beat goalkeeper Julian Pollersbeck. A few moments later, Savanier converted a penalty after a cross from Wahi hit Thiago Mendes’ arm.
The hosts retook the lead with a low shot from Houssem Aouar in the 64th minute. Karl Toko Ekambi then made it 4-2 and Houssem Aouar completed the scoring in stoppage time.
Saturday’s Ligue 1 game between St Etienne and Monaco was interrupted during the second half when fireworks were lit in the Geoffroy Guichard stands.
Referee Bastien Dechepy had ordered the players to go back to the dressing room in the 67th minute. The game restarted, after a break that lasted almost half an hour, following a meeting between the referee and local authorities.
Monaco went on to win the game 4-1.
